Young Jeezy is currently behind bars for possession of an assault rifle ... and TMZ has learned the weapon turned up during the investigation into the deadly shooting at Wiz Khalifa 's concert Friday night. Irvine PD executed a search warrant on the rapper's tour bus Sunday at the Verizon Wireless Amphitheater in connection with the shooting in Mountain View, CA ... where a man died after being shot 5 times. Jeezy's being held on $1,000,000 bail -- and he's still in custody.